1. Field of the Invention
The invention relates to an apparatus and method for installing sectional sewer and drainage pipe.
2. Description of the Related Art
The installation of sewer and drainage pipe requires that the sections of pipe installed be first connected together and properly aligned within the trench so that the pipe is level. In some locations, local codes and conditions require that the pipe be set at a slight slope (colloquially called "pitch") so that liquid being transported will flow properly. After the pipe is in position according to the planned course, the area must be appropriately back-filled with crushed stone, sand, or other material depending on the particular application and depending on local conditions and local building codes. The first problem to overcome is the task of accurately placing the pipe in the location necessary to achieve the required function. Deviations in lateral position or, in particular, grade level can destroy the effectiveness of the system. The second difficulty in the procedure is to keep the pipe from moving while the back-fill material is being placed around the positioned pipe. The back-fill material which is often crushed rock will cause the pipe to move from its intended location unless the pipe is held firmly in place. These problems must be solved in consideration of cost constraints which dictate efficient placement, back-filling with a minimum amount of labor and extra equipment.
Various devices and methods have been designed to solve these problems. The back-fill material can be leveled in the trench to provide support for the pipe before placing the pipe in the trench. This approach is extremely labor intensive.
Drainage pipe has also been installed by the use of grade stakes to provide the position and grade of the pipe. A grade board is then fastened to the stakes and back-fill material is filled to the grade board level. Then, the pipe is fastened together on the grade board, and the remaining back-fill is deposited. Again, this method is labor intensive and adds significant cost to the installed system.
U.S. Pat. No. 3,568,455, discloses a method of installing pipe using removable supports. The supports permit the pipe to be first positioned within a trench or on a drainage field in the required location. Using thumb-screw mechanisms, the supports are adjusted to the desired height of back-fill material that will be placed below the pipe and for the depth that the supports will be embedded in the ground. Then, the trench is back-filled to the level at which the pipe is supported and the pipe supports are removed. This method requires a two-step back-filling method and extra time to remove the supports. Further, the removal of the apparatus is likely to result in some changes in the position of pipe.
Another approach is disclosed in U.S. Pat. No. 4,268,189. In this design, clamps are placed along the pipe which fasten the pipe to a longitudinal support arm. This arm is in turn anchored within the trench by an anchoring mechanism. The device and procedure requires substantial additional effort to fasten and remove the device. In addition to the added labor cost, the apparatus, itself, adds to the overall cost of installation due to the numerous metal parts to fabricate and assemble.
U.S. Pat. Nos. 4,268,190; 3,512,246; 317,158 disclose inventions relating to the pipe laying art and are of general interest.
A cost effective solution for laying drainage pipe that solves the two problems (positioning the pipe within the trench and maintaining the position of the pipe during the back-filling process) is not found in the prior art.